/*
 * conversion functions between pg_wchar and multibyte streams.
 * Tatsuo Ishii
 * src/backend/utils/mb/wchar.c
 *
 */
/* can be used in either frontend or backend */
#ifdef FRONTEND
#include "postgres_fe.h"
#ifndef Assert
#define Assert(condition)
#endif
#else
#include "postgres.h"
#include "knl/knl_variable.h"
#include "commands/copy.h"

#endif

#include "mb/pg_wchar.h"

/*
 * In today's multibyte encodings other than UTF8, this two-byte sequence
 * ensures pg_encoding_mblen() == 2 && pg_encoding_verifymbstr() == 0.
 *
 * For historical reasons, several verifychar implementations opt to reject
 * this pair specifically.  Byte pair range constraints, in encoding
 * originator documentation, always excluded this pair.  No core conversion
 * could translate it.  However, longstanding verifychar implementations
 * accepted any non-NUL byte.  big5_to_euc_tw and big5_to_mic even translate
 * pairs not valid per encoding originator documentation.  To avoid tightening
 * core or non-core conversions in a security patch, we sought this one pair.
 *
 * PQescapeString() historically used spaces for BYTE1; many other values
 * could suffice for BYTE1.
 */
#define NONUTF8_INVALID_BYTE0 (0x8d)
#define NONUTF8_INVALID_BYTE1 (' ')

/*
 * conversion to pg_wchar is done by "table driven."
 * to add an encoding support, define mb2wchar_with_len(), mblen(), dsplen()
 * for the particular encoding. Note that if the encoding is only
 * supported in the client, you don't need to define
 * mb2wchar_with_len() function (SJIS is the case).
 *
 * These functions generally assume that their input is validly formed.
 * The "verifier" functions, further down in the file, have to be more
 * paranoid.  We expect that mblen() does not need to examine more than
 * the first byte of the character to discover the correct length.
 *
 * Note: for the display output of psql to work properly, the return values
 * of the dsplen functions must conform to the Unicode standard. In particular
 * the NUL character is zero width and control characters are generally
 * width -1. It is recommended that non-ASCII encodings refer their ASCII
 * subset to the ASCII routines to ensure consistency.
 */

/*
 * SQL/ASCII
 */
static int pg_ascii2wchar_with_len(const unsigned char* from, pg_wchar* to, int len)
{
    int cnt = 0;

    while (len > 0 && *from) {
        *to++ = *from++;
        len--;
        cnt++;
    }
    *to = 0;
    return cnt;
}

static int pg_ascii_mblen(const unsigned char* s)
{
    return 1;
}

static int pg_ascii_dsplen(const unsigned char* s)
{
    if (*s == '\0') {
        return 0;
    }
    if (*s < 0x20 || *s == 0x7f) {
        return -1;
    }

    return 1;
}

/*
 * EUC
 */
static int pg_euc2wchar_with_len(const unsigned char* from, pg_wchar* to, int len)
{
    int cnt = 0;

    while (len > 0 && *from) {
        if (*from == SS2 && len >= 2) { // JIS X 0201 (so called "1 byte KANA")
            from++;
            *to = (SS2 << 8) | *from++;
            len -= 2;
        } else if (*from == SS3 && len >= 3) { // JIS X 0212 KANJI
            from++;
            *to = (SS3 << 16) | (*from++ << 8);
            *to |= *from++;
            len -= 3;
        } else if (IS_HIGHBIT_SET(*from) && len >= 2) { // JIS X 0208 KANJI
            *to = *from++ << 8;
            *to |= *from++;
            len -= 2;
        } else { // must be ASCII
            *to = *from++;
            len--;
        }
        to++;
        cnt++;
    }
    *to = 0;
    return cnt;
}

static inline int pg_euc_mblen(const unsigned char* s)
{
    int len;

    if (*s == SS2) {
        len = 2;
    } else if (*s == SS3) {
        len = 3;
    } else if (IS_HIGHBIT_SET(*s)) {
        len = 2;
    } else {
        len = 1;
    }

    return len;
}

static inline int pg_euc_dsplen(const unsigned char* s)
{
    int len;

    if (*s == SS2) {
        len = 2;
    } else if (*s == SS3) {
        len = 2;
    } else if (IS_HIGHBIT_SET(*s)) {
        len = 2;
    } else {
        len = pg_ascii_dsplen(s);
    }

    return len;
}

/*
 * EUC_JP
 */
static int pg_eucjp2wchar_with_len(const unsigned char* from, pg_wchar* to, int len)
{
    return pg_euc2wchar_with_len(from, to, len);
}

static int pg_eucjp_mblen(const unsigned char* s)
{
    return pg_euc_mblen(s);
}

static int pg_eucjp_dsplen(const unsigned char* s)
{
    int len;

    if (*s == SS2) {
        len = 1;
    } else if (*s == SS3) {
        len = 2;
    } else if (IS_HIGHBIT_SET(*s)) {
        len = 2;
    } else {
        len = pg_ascii_dsplen(s);
    }

    return len;
}

/*
 * EUC_KR
 */
static int pg_euckr2wchar_with_len(const unsigned char* from, pg_wchar* to, int len)
{
    return pg_euc2wchar_with_len(from, to, len);
}

static int pg_euckr_mblen(const unsigned char* s)
{
    return pg_euc_mblen(s);
}

static int pg_euckr_dsplen(const unsigned char* s)
{
    return pg_euc_dsplen(s);
}

/*
 * EUC_CN
 *
 */
static int pg_euccn2wchar_with_len(const unsigned char* from, pg_wchar* to, int len)
{
    int cnt = 0;

    while (len > 0 && *from) {
        if (*from == SS2 && len >= 3) { // code set 2 (unused?)
            from++;
            *to = (SS2 << 16) | (*from++ << 8);
            *to |= *from++;
            len -= 3;
        } else if (*from == SS3 && len >= 3) { // code set 3 (unused ?)
            from++;
            *to = (SS3 << 16) | (*from++ << 8);
            *to |= *from++;
            len -= 3;
        } else if (IS_HIGHBIT_SET(*from) && len >= 2) { // code set 1
            *to = *from++ << 8;
            *to |= *from++;
            len -= 2;
        } else {
            *to = *from++;
            len--;
        }
        to++;
        cnt++;
    }
    *to = 0;
    return cnt;
}

static int pg_euccn_mblen(const unsigned char* s)
{
    int len;

    if (IS_HIGHBIT_SET(*s)) {
        len = 2;
    } else {
        len = 1;
    }

    return len;
}

static int pg_euccn_dsplen(const unsigned char* s)
{
    int len;

    if (IS_HIGHBIT_SET(*s)) {
        len = 2;
    } else {
        len = pg_ascii_dsplen(s);
    }

    return len;
}

/*
 * EUC_TW
 *
 */
static int pg_euctw2wchar_with_len(const unsigned char* from, pg_wchar* to, int len)
{
    int cnt = 0;

    while (len > 0 && *from) {
        if (*from == SS2 && len >= 4) { // code set 2
            from++;
            *to = (((uint32)SS2) << 24) | (*from++ << 16);
            *to |= *from++ << 8;
            *to |= *from++;
            len -= 4;
        } else if (*from == SS3 && len >= 3) { // code set 3 (unused?)
            from++;
            *to = (SS3 << 16) | (*from++ << 8);
            *to |= *from++;
            len -= 3;
        } else if (IS_HIGHBIT_SET(*from) && len >= 2) { // code set 2
            *to = *from++ << 8;
            *to |= *from++;
            len -= 2;
        } else {
            *to = *from++;
            len--;
        }
        to++;
        cnt++;
    }
    *to = 0;
    return cnt;
}

static int pg_euctw_mblen(const unsigned char* s)
{
    int len;

    if (*s == SS2) {
        len = 4;
    } else if (*s == SS3) {
        len = 3;
    } else if (IS_HIGHBIT_SET(*s)) {
        len = 2;
    } else {
        len = 1;
    }

    return len;
}

static int pg_euctw_dsplen(const unsigned char* s)
{
    int len;

    if (*s == SS2) {
        len = 2;
    } else if (*s == SS3) {
        len = 2;
    } else if (IS_HIGHBIT_SET(*s)) {
        len = 2;
    } else {
        len = pg_ascii_dsplen(s);
    }

    return len;
}

/*
 * Convert pg_wchar to EUC_* encoding.
 * caller must allocate enough space for "to", including a trailing zero!
 * len: length of from.
 * "from" not necessarily null terminated.
 */
static int pg_wchar2euc_with_len(const pg_wchar* from, unsigned char* to, int len)
{
    int cnt = 0;

    while (len > 0 && *from) {
        unsigned char c;

        if ((c = (*from >> 24))) {
            *to++ = c;
            *to++ = (*from >> 16) & 0xff;
            *to++ = (*from >> 8) & 0xff;
            *to++ = *from & 0xff;
            cnt += 4;
        } else if ((c = (*from >> 16))) {
            *to++ = c;
            *to++ = (*from >> 8) & 0xff;
            *to++ = *from & 0xff;
            cnt += 3;
        } else if ((c = (*from >> 8))) {
            *to++ = c;
            *to++ = *from & 0xff;
            cnt += 2;
        } else {
            *to++ = *from;
            cnt++;
        }
        from++;
        len--;
    }
    *to = 0;
    return cnt;
}

/*
 * JOHAB
 */
static int pg_johab_mblen(const unsigned char* s)
{
    return pg_euc_mblen(s);
}

static int pg_johab_dsplen(const unsigned char* s)
{
    return pg_euc_dsplen(s);
}

/*
 * convert UTF8 string to pg_wchar (UCS-4)
 * caller must allocate enough space for "to", including a trailing zero!
 * len: length of from.
 * "from" not necessarily null terminated.
 */
static int pg_utf2wchar_with_len(const unsigned char* from, pg_wchar* to, int len)
{
    int cnt = 0;
    uint32 c1, c2, c3, c4;

    while (len > 0 && *from) {
        if ((*from & 0x80) == 0) {
            *to = *from++;
            len--;
        } else if ((*from & 0xe0) == 0xc0) {
            if (len < 2) {
                break; // drop trailing incomplete char
            }
            c1 = *from++ & 0x1f;
            c2 = *from++ & 0x3f;
            *to = (c1 << 6) | c2;
            len -= 2;
        } else if ((*from & 0xf0) == 0xe0) {
            if (len < 3) {
                break; // drop trailing incomplete char
            }
            c1 = *from++ & 0x0f;
            c2 = *from++ & 0x3f;
            c3 = *from++ & 0x3f;
            *to = (c1 << 12) | (c2 << 6) | c3;
            len -= 3;
        } else if ((*from & 0xf8) == 0xf0) {
            if (len < 4) {
                break; // drop trailing incomplete char
            }
            c1 = *from++ & 0x07;
            c2 = *from++ & 0x3f;
            c3 = *from++ & 0x3f;
            c4 = *from++ & 0x3f;
            *to = (c1 << 18) | (c2 << 12) | (c3 << 6) | c4;
            len -= 4;
        } else {
            // treat a bogus char as length 1; not ours to raise error
            *to = *from++;
            len--;
        }
        to++;
        cnt++;
    }
    *to = 0;
    return cnt;
}

/*
 * Map a Unicode code point to UTF-8.  utf8string must have 4 bytes of
 * space allocated.
 */
unsigned char* unicode_to_utf8(pg_wchar c, unsigned char* utf8string)
{
    if (c <= 0x7F) {
        utf8string[0] = c;
    } else if (c <= 0x7FF) {
        utf8string[0] = 0xC0 | ((c >> 6) & 0x1F);
        utf8string[1] = 0x80 | (c & 0x3F);
    } else if (c <= 0xFFFF) {
        utf8string[0] = 0xE0 | ((c >> 12) & 0x0F);
        utf8string[1] = 0x80 | ((c >> 6) & 0x3F);
        utf8string[2] = 0x80 | (c & 0x3F);
    } else {
        utf8string[0] = 0xF0 | ((c >> 18) & 0x07);
        utf8string[1] = 0x80 | ((c >> 12) & 0x3F);
        utf8string[2] = 0x80 | ((c >> 6) & 0x3F);
        utf8string[3] = 0x80 | (c & 0x3F);
    }

    return utf8string;
}

/*
 * Trivial conversion from pg_wchar to UTF-8.
 * caller should allocate enough space for "to"
 * len: length of from.
 * "from" not necessarily null terminated.
 */
static int pg_wchar2utf_with_len(const pg_wchar* from, unsigned char* to, int len)
{
    int cnt = 0;

    while (len > 0 && *from) {
        int char_len;

        unicode_to_utf8(*from, to);
        char_len = pg_utf_mblen(to);
        cnt += char_len;
        to += char_len;
        from++;
        len--;
    }
    *to = 0;
    return cnt;
}

/*
 * Return the byte length of a UTF8 character pointed to by s
 *
 * Note: in the current implementation we do not support UTF8 sequences
 * of more than 4 bytes; hence do NOT return a value larger than 4.
 * We return "1" for any leading byte that is either flat-out illegal or
 * indicates a length larger than we support.
 *
 * pg_utf2wchar_with_len(), utf8_to_unicode(), pg_utf8_islegal(), and perhaps
 * other places would need to be fixed to change this.
 */
int pg_utf_mblen(const unsigned char* s)
{
    int len;

    if ((*s & 0x80) == 0) {
        len = 1;
    } else if ((*s & 0xe0) == 0xc0) {
        len = 2;
    } else if ((*s & 0xf0) == 0xe0) {
        len = 3;
    } else if ((*s & 0xf8) == 0xf0) {
        len = 4;
    }
#ifdef NOT_USED
    else if ((*s & 0xfc) == 0xf8) {
        len = 5;
    } else if ((*s & 0xfe) == 0xfc) {
        len = 6;
    }
#endif
    else {
        len = 1;
    }

    return len;
}

/*
 * This is an implementation of wcwidth() and wcswidth() as defined in
 * "The Single UNIX Specification, Version 2, The Open Group, 1997"
 * <http://www.UNIX-systems.org/online.html>
 *
 * Markus Kuhn -- 2001-09-08 -- public domain
 *
 * customised for PostgreSQL
 *
 * original available at : http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
 */

struct mbinterval {
    unsigned short first;
    unsigned short last;
};

/* auxiliary function for binary search in interval table */
static int mbbisearch(pg_wchar ucs, const struct mbinterval* table, int max)
{
    int min = 0;
    int mid;

    if (ucs < table[0].first || ucs > table[max].last) {
        return 0;
    }

    while (max >= min) {
        mid = (min + max) / 2;
        if (ucs > table[mid].last) {
            min = mid + 1;
        } else if (ucs < table[mid].first) {
            max = mid - 1;
        } else {
            return 1;
        }
    }

    return 0;
}

/* The following functions define the column width of an ISO 10646
 * character as follows:
 *
 *	  - The null character (U+0000) has a column width of 0.
 *
 *	  - Other C0/C1 control characters and DEL will lead to a return
 *		value of -1.
 *
 *	  - Non-spacing and enclosing combining characters (general
 *		category code Mn or Me in the Unicode database) have a
 *		column width of 0.
 *
 *	  - Other format characters (general category code Cf in the Unicode
 *		database) and ZERO WIDTH SPACE (U+200B) have a column width of 0.
 *
 *	  - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF)
 *		have a column width of 0.
 *
 *	  - Spacing characters in the East Asian Wide (W) or East Asian
 *		FullWidth (F) category as defined in Unicode Technical
 *		Report #11 have a column width of 2.
 *
 *	  - All remaining characters (including all printable
 *		ISO 8859-1 and WGL4 characters, Unicode control characters,
 *		etc.) have a column width of 1.
 *
 * This implementation assumes that wchar_t characters are encoded
 * in ISO 10646.
 */

static int ucs_wcwidth(pg_wchar ucs)
{
    /* sorted list of non-overlapping intervals of non-spacing characters */
    static const struct mbinterval combining[] = {{0x0300, 0x034E},
        {0x0360, 0x0362},
        {0x0483, 0x0486},
        {0x0488, 0x0489},
        {0x0591, 0x05A1},
        {0x05A3, 0x05B9},
        {0x05BB, 0x05BD},
        {0x05BF, 0x05BF},
        {0x05C1, 0x05C2},
        {0x05C4, 0x05C4},
        {0x064B, 0x0655},
        {0x0670, 0x0670},
        {0x06D6, 0x06E4},
        {0x06E7, 0x06E8},
        {0x06EA, 0x06ED},
        {0x070F, 0x070F},
        {0x0711, 0x0711},
        {0x0730, 0x074A},
        {0x07A6, 0x07B0},
        {0x0901, 0x0902},
        {0x093C, 0x093C},
        {0x0941, 0x0948},
        {0x094D, 0x094D},
        {0x0951, 0x0954},
        {0x0962, 0x0963},
        {0x0981, 0x0981},
        {0x09BC, 0x09BC},
        {0x09C1, 0x09C4},
        {0x09CD, 0x09CD},
        {0x09E2, 0x09E3},
        {0x0A02, 0x0A02},
        {0x0A3C, 0x0A3C},
        {0x0A41, 0x0A42},
        {0x0A47, 0x0A48},
        {0x0A4B, 0x0A4D},
        {0x0A70, 0x0A71},
        {0x0A81, 0x0A82},
        {0x0ABC, 0x0ABC},
        {0x0AC1, 0x0AC5},
        {0x0AC7, 0x0AC8},
        {0x0ACD, 0x0ACD},
        {0x0B01, 0x0B01},
        {0x0B3C, 0x0B3C},
        {0x0B3F, 0x0B3F},
        {0x0B41, 0x0B43},
        {0x0B4D, 0x0B4D},
        {0x0B56, 0x0B56},
        {0x0B82, 0x0B82},
        {0x0BC0, 0x0BC0},
        {0x0BCD, 0x0BCD},
        {0x0C3E, 0x0C40},
        {0x0C46, 0x0C48},
        {0x0C4A, 0x0C4D},
        {0x0C55, 0x0C56},
        {0x0CBF, 0x0CBF},
        {0x0CC6, 0x0CC6},
        {0x0CCC, 0x0CCD},
        {0x0D41, 0x0D43},
        {0x0D4D, 0x0D4D},
        {0x0DCA, 0x0DCA},
        {0x0DD2, 0x0DD4},
        {0x0DD6, 0x0DD6},
        {0x0E31, 0x0E31},
        {0x0E34, 0x0E3A},
        {0x0E47, 0x0E4E},
        {0x0EB1, 0x0EB1},
        {0x0EB4, 0x0EB9},
        {0x0EBB, 0x0EBC},
        {0x0EC8, 0x0ECD},
        {0x0F18, 0x0F19},
        {0x0F35, 0x0F35},
        {0x0F37, 0x0F37},
        {0x0F39, 0x0F39},
        {0x0F71, 0x0F7E},
        {0x0F80, 0x0F84},
        {0x0F86, 0x0F87},
        {0x0F90, 0x0F97},
        {0x0F99, 0x0FBC},
        {0x0FC6, 0x0FC6},
        {0x102D, 0x1030},
        {0x1032, 0x1032},
        {0x1036, 0x1037},
        {0x1039, 0x1039},
        {0x1058, 0x1059},
        {0x1160, 0x11FF},
        {0x17B7, 0x17BD},
        {0x17C6, 0x17C6},
        {0x17C9, 0x17D3},
        {0x180B, 0x180E},
        {0x18A9, 0x18A9},
        {0x200B, 0x200F},
        {0x202A, 0x202E},
        {0x206A, 0x206F},
        {0x20D0, 0x20E3},
        {0x302A, 0x302F},
        {0x3099, 0x309A},
        {0xFB1E, 0xFB1E},
        {0xFE20, 0xFE23},
        {0xFEFF, 0xFEFF},
        {0xFFF9, 0xFFFB}};

    /* test for 8-bit control characters */
    if (ucs == 0) {
        return 0;
    }

    if (ucs < 0x20 || (ucs >= 0x7f && ucs < 0xa0) || ucs > 0x0010ffff) {
        return -1;
    }

    /* binary search in table of non-spacing characters */
    if (mbbisearch(ucs, combining, sizeof(combining) / sizeof(struct mbinterval) - 1)) {
        return 0;
    }

    /*
     * if we arrive here, ucs is not a combining or C0/C1 control character
     */

    return 1 +
           (int)(ucs >= 0x1100 &&
               (ucs <= 0x115f || // Hangul Jamo init. consonants
                   (ucs >= 0x2e80 && ucs <= 0xa4cf && (ucs & ~0x0011) != 0x300a && ucs != 0x303f) || // CJK ... Yi
                   (ucs >= 0xac00 && ucs <= 0xd7a3) || // Hangul Syllables
                   (ucs >= 0xf900 && ucs <= 0xfaff) || // CJK Compatibility Ideographs
                   (ucs >= 0xfe30 && ucs <= 0xfe6f) || // CJK Compatibility Forms
                   (ucs >= 0xff00 && ucs <= 0xff5f) || // Fullwidth Forms
                   (ucs >= 0xffe0 && ucs <= 0xffe6) || (ucs >= 0x20000 && ucs <= 0x2ffff)));
}

/*
 * Convert a UTF-8 character to a Unicode code point.
 * This is a one-character version of pg_utf2wchar_with_len.
 *
 * No error checks here, c must point to a long-enough string.
 */
pg_wchar utf8_to_unicode(const unsigned char* c)
{
    if ((*c & 0x80) == 0) {
        return (pg_wchar)c[0];
    } else if ((*c & 0xe0) == 0xc0) {
        return (pg_wchar)(((c[0] & 0x1f) << 6) | (c[1] & 0x3f));
    } else if ((*c & 0xf0) == 0xe0) {
        return (pg_wchar)(((c[0] & 0x0f) << 12) | ((c[1] & 0x3f) << 6) | (c[2] & 0x3f));
    } else if ((*c & 0xf8) == 0xf0) {
        return (pg_wchar)(((c[0] & 0x07) << 18) | ((c[1] & 0x3f) << 12) | ((c[2] & 0x3f) << 6) | (c[3] & 0x3f));
    } else {
        // that is an invalid code on purpose
        return 0xffffffff;
    }
}

static int pg_utf_dsplen(const unsigned char* s)
{
    return ucs_wcwidth(utf8_to_unicode(s));
}

/*
 * convert mule internal code to pg_wchar
 * caller should allocate enough space for "to"
 * len: length of from.
 * "from" not necessarily null terminated.
 */
static int pg_mule2wchar_with_len(const unsigned char* from, pg_wchar* to, int len)
{
    int cnt = 0;

    while (len > 0 && *from) {
        if (IS_LC1(*from) && len >= 2) {
            *to = *from++ << 16;
            *to |= *from++;
            len -= 2;
        } else if (IS_LCPRV1(*from) && len >= 3) {
            from++;
            *to = *from++ << 16;
            *to |= *from++;
            len -= 3;
        } else if (IS_LC2(*from) && len >= 3) {
            *to = *from++ << 16;
            *to |= *from++ << 8;
            *to |= *from++;
            len -= 3;
        } else if (IS_LCPRV2(*from) && len >= 4) {
            from++;
            *to = *from++ << 16;
            *to |= *from++ << 8;
            *to |= *from++;
            len -= 4;
        } else { // assume ASCII
            *to = (unsigned char)*from++;
            len--;
        }
        to++;
        cnt++;
    }
    *to = 0;
    return cnt;
}

/*
 * convert pg_wchar to mule internal code
 * caller should allocate enough space for "to"
 * len: length of from.
 * "from" not necessarily null terminated.
 */
static int pg_wchar2mule_with_len(const pg_wchar* from, unsigned char* to, int len)
{
    int cnt = 0;

    while (len > 0 && *from) {
        unsigned char lb;

        lb = (*from >> 16) & 0xff;
        if (IS_LC1(lb)) {
            *to++ = lb;
            *to++ = *from & 0xff;
            cnt += 2;
        } else if (IS_LC2(lb)) {
            *to++ = lb;
            *to++ = (*from >> 8) & 0xff;
            *to++ = *from & 0xff;
            cnt += 3;
        } else if (IS_LCPRV1_A_RANGE(lb)) {
            *to++ = LCPRV1_A;
            *to++ = lb;
            *to++ = *from & 0xff;
            cnt += 3;
        } else if (IS_LCPRV1_B_RANGE(lb)) {
            *to++ = LCPRV1_B;
            *to++ = lb;
            *to++ = *from & 0xff;
            cnt += 3;
        } else if (IS_LCPRV2_A_RANGE(lb)) {
            *to++ = LCPRV2_A;
            *to++ = lb;
            *to++ = (*from >> 8) & 0xff;
            *to++ = *from & 0xff;
            cnt += 4;
        } else if (IS_LCPRV2_B_RANGE(lb)) {
            *to++ = LCPRV2_B;
            *to++ = lb;
            *to++ = (*from >> 8) & 0xff;
            *to++ = *from & 0xff;
            cnt += 4;
        } else {
            *to++ = *from & 0xff;
            cnt += 1;
        }
        from++;
        len--;
    }
    *to = 0;
    return cnt;
}

int pg_mule_mblen(const unsigned char* s)
{
    int len;

    if (IS_LC1(*s)) {
        len = 2;
    } else if (IS_LCPRV1(*s)) {
        len = 3;
    } else if (IS_LC2(*s)) {
        len = 3;
    } else if (IS_LCPRV2(*s)) {
        len = 4;
    } else {
        len = 1; /* assume ASCII */
    }
    return len;
}

static int pg_mule_dsplen(const unsigned char* s)
{
    int len;

    if (IS_LC1(*s)) {
        len = 1;
    } else if (IS_LCPRV1(*s)) {
        len = 1;
    } else if (IS_LC2(*s)) {
        len = 2;
    } else if (IS_LCPRV2(*s)) {
        len = 2;
    } else {
        len = 1; /* assume ASCII */
    }
    return len;
}

/*
 * ISO8859-1
 */
static int pg_latin12wchar_with_len(const unsigned char* from, pg_wchar* to, int len)
{
    int cnt = 0;

    while (len > 0 && *from) {
        *to++ = *from++;
        len--;
        cnt++;
    }
    *to = 0;
    return cnt;
}

/*
 * Trivial conversion from pg_wchar to single byte encoding. Just ignores
 * high bits.
 * caller should allocate enough space for "to"
 * len: length of from.
 * "from" not necessarily null terminated.
 */
static int pg_wchar2single_with_len(const pg_wchar* from, unsigned char* to, int len)
{
    int cnt = 0;

    while (len > 0 && *from) {
        *to++ = *from++;
        len--;
        cnt++;
    }
    *to = 0;
    return cnt;
}

static int pg_latin1_mblen(const unsigned char* s)
{
    return 1;
}

static int pg_latin1_dsplen(const unsigned char* s)
{
    return pg_ascii_dsplen(s);
}

/*
 * SJIS
 */
static int pg_sjis_mblen(const unsigned char* s)
{
    int len;

    if (*s >= 0xa1 && *s <= 0xdf) {
        len = 1; // 1 byte kana?
    } else if (IS_HIGHBIT_SET(*s)) {
        len = 2; // kanji?
    } else {
        len = 1; // should be ASCII
    }
    return len;
}

static int pg_sjis_dsplen(const unsigned char* s)
{
    int len;

    if (*s >= 0xa1 && *s <= 0xdf) {
        len = 1; // 1 byte kana?
    } else if (IS_HIGHBIT_SET(*s)) {
        len = 2; // kanji?
    } else {
        len = pg_ascii_dsplen(s); // should be ASCII
    }
    return len;
}

/*
 * Big5
 */
static int pg_big5_mblen(const unsigned char* s)
{
    int len;

    if (IS_HIGHBIT_SET(*s)) {
        len = 2; /* kanji? */
    } else {
        len = 1; /* should be ASCII */
    }
    return len;
}

static int pg_big5_dsplen(const unsigned char* s)
{
    int len;

    if (IS_HIGHBIT_SET(*s)) {
        len = 2; /* kanji? */
    } else {
        len = pg_ascii_dsplen(s); /* should be ASCII */
    }
    return len;
}

/*
 * GBK
 */
// Trivial conversion from GBK to pg_wchar.
// caller should allocate enough space for "to"
// len: length of from.
// "from" not necessarily null terminated.
static int pg_gbk2wchar_with_len(const unsigned char* from, pg_wchar* to, int len)
{
    int cnt = 0;

    while (len > 0 && *from) {
        if (IS_HIGHBIT_SET(*from)) { // kanji?
            *to = *(short*)from;
            to++;
            from += 2;
            len -= 2;
        } else { // should be ASCII
            *to++ = *from++;
            len--;
        }
        cnt++;
    }
    *to = 0;
    return cnt;
}

// Trivial conversion from pg_wchar to GBK.
// caller should allocate enough space for "to"
// len: length of from.
// "from" not necessarily null terminated.
static int pg_wchar2gbk_with_len(const pg_wchar* from, unsigned char* to, int len)
{
    int cnt = 0;

    while (len > 0 && *from) {
        const unsigned char* wchar = (const unsigned char*)from;
        if (IS_HIGHBIT_SET(*wchar)) { // kanji?
            *to = *(char*)from;
            from++;
            to += 2;
            len -= 2;
        } else { // should be ASCII
            *to++ = *from++;
            len--;
        }
        cnt++;
    }
    *to = 0;
    return cnt;
}

static int pg_gbk_mblen(const unsigned char* s)
{
    int len;

    if (IS_HIGHBIT_SET(*s)) {
        len = 2; /* kanji? */
    } else {
        len = 1; /* should be ASCII */
    }
    return len;
}

static int pg_gbk_dsplen(const unsigned char* s)
{
    int len;

    if (IS_HIGHBIT_SET(*s)) {
        len = 2; /* kanji? */
    } else {
        len = pg_ascii_dsplen(s); /* should be ASCII */
    }
    return len;
}

/*
 * UHC
 */
static int pg_uhc_mblen(const unsigned char* s)
{
    int len;

    if (IS_HIGHBIT_SET(*s)) {
        len = 2; /* 2byte? */
    } else {
        len = 1; /* should be ASCII */
    }
    return len;
}

static int pg_uhc_dsplen(const unsigned char* s)
{
    int len;

    if (IS_HIGHBIT_SET(*s)) {
        len = 2; /* 2byte? */
    } else {
        len = pg_ascii_dsplen(s); /* should be ASCII */
    }
    return len;
}

/*
 *	* GB18030
 *	 * Added by Bill Huang <bhuang@redhat.com>,<bill_huanghb@ybb.ne.jp>
 *	  */
static int pg_gb180302wchar_with_len(const unsigned char* from, pg_wchar* to, int len)
{
    int cnt = 0;
    while (len > 0) {
        if (*from <= 0x7f) { /* ASCII */
            *to = *from++;
            --len;
        } else if (IS_HIGHBIT_SET(*from) &&
                    (*(from + 1) >= 0x30 && *(from + 1) < 0x40)) {
            if (len < 4) {
                break;            /* drop trailing incomplete char */
            }
            *to  = *from++ << 24;
            *to |= *from++ << 16;
            *to |= *from++ << 8;
            *to |= *from++;
            len -= 4;
        } else {
            if (len < 2) {
                break;
            }
            *to  = *from++ << 8;
            *to |= *from++;
            len -= 2;
        }
        ++to;
        ++cnt;
    }
    *to = 0;
    return cnt;
}

static int pg_wchar2gb18030_with_len(const pg_wchar* from, unsigned char* to, int len)
{
    int cnt = 0;
    while (len > 0 && *from) {
        unsigned char c;
        if ((c = (*from >> 24))) {
            *to++ = c;
            *to++ = (*from >> 16) & 0xff;
            *to++ = (*from >> 8) & 0xff;
            *to++ = *from & 0xff;
            cnt += 4;
        } else if ((c = (*from >> 8))) {
            *to++ = c;
            *to++ = *from & 0xff;
            cnt += 2;
        } else {
            *to++ = *from;
            cnt++;
        }
        from++;
        len--;
    }
    *to = 0;
    return cnt;
}

static int pg_gb18030_mblen(const unsigned char* s)
{
    int len;

    if (!IS_HIGHBIT_SET(*s)) {
        len = 1; /* ASCII */
    } else {
        if ((*(s + 1) >= 0x40 && *(s + 1) <= 0x7e) || (*(s + 1) >= 0x80 && *(s + 1) <= 0xfe)) {
            len = 2;
        } else if (*(s + 1) >= 0x30 && *(s + 1) <= 0x39) {
            len = 4;
        } else {
            len = 2;
        }
    }
    return len;
}

static int pg_gb18030_dsplen(const unsigned char* s)
{
    int len;

    if (IS_HIGHBIT_SET(*s)) {
        len = 2;
    } else {
        len = pg_ascii_dsplen(s); /* ASCII */
    }
    return len;
}

/*
 * -------------------------------------------------------------------
 * multibyte sequence validators
 *
 * These functions accept "s", a pointer to the first byte of a string,
 * and "len", the remaining length of the string.  If there is a validly
 * encoded character beginning at *s, return its length in bytes; else
 * return -1.
 *
 * The functions can assume that len > 0 and that *s != '\0', but they must
 * test for and reject zeroes in any additional bytes of a multibyte character.
 *
 * Note that this definition allows the function for a single-byte
 * encoding to be just "return 1".
 * -------------------------------------------------------------------
 */

static int pg_ascii_verifier(const unsigned char* s, int len)
{
    return 1;
}

#define IS_EUC_RANGE_VALID(c) ((c) >= 0xa1 && (c) <= 0xfe)

static int pg_eucjp_verifier(const unsigned char* s, int len)
{
    int l;
    unsigned char c1, c2;

    c1 = *s++;

    switch (c1) {
        case SS2: /* JIS X 0201 */
            l = 2;
            if (l > len) {
                return -1;
            }

            c2 = *s++;
            if (c2 < 0xa1 || c2 > 0xdf) {
                return -1;
            }

            break;

        case SS3: /* JIS X 0212 */
            l = 3;
            if (l > len) {
                return -1;
            }

            c2 = *s++;
            if (!IS_EUC_RANGE_VALID(c2)) {
                return -1;
            }

            c2 = *s++;
            if (!IS_EUC_RANGE_VALID(c2)) {
                return -1;
            }
            break;

        default:
            if (IS_HIGHBIT_SET(c1)) { // JIS X 0208?
                l = 2;
                if (l > len) {
                    return -1;
                }
                if (!IS_EUC_RANGE_VALID(c1)) {
                    return -1;
                }
                c2 = *s++;
                if (!IS_EUC_RANGE_VALID(c2)) {
                    return -1;
                }
            } else { // must be ASCII
                l = 1;
            }
            break;
    }

    return l;
}

static int pg_euckr_verifier(const unsigned char* s, int len)
{
    int l;
    unsigned char c1, c2;

    c1 = *s++;

    if (IS_HIGHBIT_SET(c1)) {
        l = 2;
        if (l > len) {
            return -1;
        }
        if (!IS_EUC_RANGE_VALID(c1)) {
            return -1;
        }
        c2 = *s++;
        if (!IS_EUC_RANGE_VALID(c2)) {
            return -1;
        }
    } else { // must be ASCII
        l = 1;
    }

    return l;
}

/* EUC-CN byte sequences are exactly same as EUC-KR */
#define pg_euccn_verifier pg_euckr_verifier

static int pg_euctw_verifier(const unsigned char* s, int len)
{
    int l;
    unsigned char c1, c2;

    c1 = *s++;

    switch (c1) {
        case SS2: /* CNS 11643 Plane 1-7 */
            l = 4;
            if (l > len) {
                return -1;
            }

            c2 = *s++;
            if (c2 < 0xa1 || c2 > 0xa7) {
                return -1;
            }

            c2 = *s++;
            if (!IS_EUC_RANGE_VALID(c2)) {
                return -1;
            }

            c2 = *s++;
            if (!IS_EUC_RANGE_VALID(c2)) {
                return -1;
            }
            break;

        case SS3: /* unused */
            return -1;

        default:
            if (IS_HIGHBIT_SET(c1)) { // CNS 11643 Plane 1
                l = 2;
                if (l > len) {
                    return -1;
                }
                // no further range check on c1?
                c2 = *s++;
                if (!IS_EUC_RANGE_VALID(c2)) {
                    return -1;
                }
            } else { // must be ASCII
                l = 1;
            }
            break;
    }
    return l;
}

static int pg_johab_verifier(const unsigned char* s, int len)
{
    int l, mbl;
    unsigned char c;

    l = mbl = pg_johab_mblen(s);

    if (len < l) {
        return -1;
    }


    if (!IS_HIGHBIT_SET(*s)) {
        return mbl;
    }


    while (--l > 0) {
        c = *++s;
        if (!IS_EUC_RANGE_VALID(c)) {
            return -1;
        }
    }
    return mbl;
}

static int pg_mule_verifier(const unsigned char* s, int len)
{
    int l, mbl;
    unsigned char c;

    l = mbl = pg_mule_mblen(s);

    if (len < l) {
        return -1;
    }

    while (--l > 0) {
        c = *++s;
        if (!IS_HIGHBIT_SET(c)) {
            return -1;
        }
    }
    return mbl;
}

static int pg_latin1_verifier(const unsigned char* s, int len)
{
    return 1;
}

static int pg_sjis_verifier(const unsigned char* s, int len)
{
    int l, mbl;
    unsigned char c1, c2;

    l = mbl = pg_sjis_mblen(s);

    if (len < l) {
        return -1;
    }

    // pg_sjis_mblen already verified it
    if (l == 1) {
        return mbl;
    }


    c1 = *s++;
    c2 = *s;
    if (!ISSJISHEAD(c1) || !ISSJISTAIL(c2)) {
        return -1;
    }

    return mbl;
}

static int pg_big5_verifier(const unsigned char* s, int len)
{
    int l, mbl;

    l = mbl = pg_big5_mblen(s);

    if (len < l) {
        return -1;
    }

    // when mbl is 2
    if (l == 2 && s[0] == NONUTF8_INVALID_BYTE0 && s[1] == NONUTF8_INVALID_BYTE1) {
        return -1;
    }

    while (--l > 0) {
        if (*++s == '\0') {
            return -1;
        }
    }

    return mbl;
}

static int pg_gbk_verifier(const unsigned char* s, int len)
{
    int l, mbl;

    l = mbl = pg_gbk_mblen(s);

    if (len < l) {
        return -1;
    }

    if (!pg_gbk_islegal(s, l)) {
        return -1;
    }

    // when mbl is 2
    if (l == 2 && s[0] == NONUTF8_INVALID_BYTE0 && s[1] == NONUTF8_INVALID_BYTE1) {
        return -1;
    }

    while (--l > 0) {
        if (*++s == '\0') {
            return -1;
        }
    }

    return mbl;
}

// check if the input character which is declared as GBK is legal
bool pg_gbk_islegal(const unsigned char* source, int length)
{
    switch (length) {
        default:
            // reject lengths > 2
            return false;
        case 2:
            if (source[0] < 0x81 || source[0] > 0xFE || source[1] < 0x40 || source[1] > 0xFE || source[1] == 0x7F) {
                return false;
            }
            break;
            // FALL THRU
        case 1:
            if (*source > 0x7F) {
                return false;
            }
            break;
    }
    return true;
}

static int pg_uhc_verifier(const unsigned char* s, int len)
{
    int l, mbl;

    l = mbl = pg_uhc_mblen(s);

    if (len < l) {
        return -1;
    }

    // when mbl is 2
    if (l == 2 && s[0] == NONUTF8_INVALID_BYTE0 && s[1] == NONUTF8_INVALID_BYTE1) {
        return -1;
    }

    while (--l > 0) {
        if (*++s == '\0') {
            return -1;
        }
    }

    return mbl;
}

static int pg_gb18030_verifier(const unsigned char* s, int len)
{
    int l, mbl;

    l = mbl = pg_gb18030_mblen(s);

    if (len < l) {
        return -1;
    }

    // when mbl is 2
    if (l == 2 && s[0] == NONUTF8_INVALID_BYTE0 && s[1] == NONUTF8_INVALID_BYTE1) {
        return -1;
    }

    while (--l > 0) {
        if (*++s == '\0') {
            return -1;
        }
    }

    return mbl;
}

static int pg_utf8_verifier(const unsigned char* s, int len)
{
    int l = pg_utf_mblen(s);

    if (len < l) {
        return -1;
    }

    if (!pg_utf8_islegal(s, l)) {
        return -1;
    }

    return l;
}

/*
 * Check for validity of a single UTF-8 encoded character
 *
 * This directly implements the rules in RFC3629.  The bizarre-looking
 * restrictions on the second byte are meant to ensure that there isn't
 * more than one encoding of a given Unicode character point; that is,
 * you may not use a longer-than-necessary byte sequence with high order
 * zero bits to represent a character that would fit in fewer bytes.
 * To do otherwise is to create security hazards (eg, create an apparent
 * non-ASCII character that decodes to plain ASCII).
 *
 * length is assumed to have been obtained by pg_utf_mblen(), and the
 * caller must have checked that that many bytes are present in the buffer.
 */
bool pg_utf8_islegal(const unsigned char* source, int length)
{
    unsigned char a;

    switch (length) {
        default:
            /* reject lengths 5 and 6 for now */
            return false;
        case 4:
            a = source[3];
            if (a < 0x80 || a > 0xBF) {
                return false;
            }
            /* FALL THRU */
        case 3:
            a = source[2];
            if (a < 0x80 || a > 0xBF) {
                return false;
            }
            /* FALL THRU */
        case 2:
            a = source[1];
            switch (*source) {
                case 0xE0:
                    if (a < 0xA0 || a > 0xBF) {
                        return false;
                    }
                    break;
                case 0xED:
                    if (a < 0x80 || a > 0x9F) {
                        return false;
                    }
                    break;
                case 0xF0:
                    if (a < 0x90 || a > 0xBF) {
                        return false;
                    }
                    break;
                case 0xF4:
                    if (a < 0x80 || a > 0x8F) {
                        return false;
                    }
                    break;
                default:
                    if (a < 0x80 || a > 0xBF) {
                        return false;
                    }
                    break;
            }
            /* FALL THRU */
        case 1:
            a = *source;
            if (a >= 0x80 && a < 0xC2) {
                return false;
            }
            if (a > 0xF4) {
                return false;
            }
            break;
    }
    return true;
}

/*
 * Fills the provided buffer with two bytes such that:
 *   pg_encoding_mblen(dst) == 2 && pg_encoding_verifymbstr(dst) == 0
 */
void pg_encoding_set_invalid(int encoding, char *dst)
{
    Assert(pg_encoding_max_length(encoding) > 1);

    dst[0] = (encoding == PG_UTF8) ? 0xc0 : NONUTF8_INVALID_BYTE0;
    dst[1] = NONUTF8_INVALID_BYTE1;
}

#ifndef FRONTEND

/*
 * Generic character incrementer function.
 *
 * Not knowing anything about the properties of the encoding in use, we just
 * keep incrementing the last byte until we get a validly-encoded result,
 * or we run out of values to try.	We don't bother to try incrementing
 * higher-order bytes, so there's no growth in runtime for wider characters.
 * (If we did try to do that, we'd need to consider the likelihood that 255
 * is not a valid final byte in the encoding.)
 */
static bool pg_generic_charinc(unsigned char* charptr, int len)
{
    unsigned char* lastbyte = charptr + len - 1;
    mbverifier mbverify;

    /* We can just invoke the character verifier directly. */
    mbverify = pg_wchar_table[GetDatabaseEncoding()].mbverify;

    while (*lastbyte < (unsigned char)255) {
        (*lastbyte)++;
        if ((*mbverify)(charptr, len) == len) {
            return true;
        }
    }

    return false;
}

/*
 * UTF-8 character incrementer function.
 *
 * For a one-byte character less than 0x7F, we just increment the byte.
 *
 * For a multibyte character, every byte but the first must fall between 0x80
 * and 0xBF; and the first byte must be between 0xC0 and 0xF4.	We increment
 * the last byte that's not already at its maximum value.  If we can't find a
 * byte that's less than the maximum allowable value, we simply fail.  We also
 * need some special-case logic to skip regions used for surrogate pair
 * handling, as those should not occur in valid UTF-8.
 *
 * Note that we don't reset lower-order bytes back to their minimums, since
 * we can't afford to make an exhaustive search (see make_greater_string).
 */
static bool pg_utf8_increment(unsigned char* charptr, int length)
{
    unsigned char a;
    unsigned char limit;

    switch (length) {
        default:
            /* reject lengths 5 and 6 for now */
            return false;
        case 4:
            a = charptr[3];
            if (a < 0xBF) {
                charptr[3]++;
                break;
            }
            /* FALL THRU */
        case 3:
            a = charptr[2];
            if (a < 0xBF) {
                charptr[2]++;
                break;
            }
            /* FALL THRU */
        case 2:
            a = charptr[1];
            switch (*charptr) {
                case 0xED:
                    limit = 0x9F;
                    break;
                case 0xF4:
                    limit = 0x8F;
                    break;
                default:
                    limit = 0xBF;
                    break;
            }
            if (a < limit) {
                charptr[1]++;
                break;
            }
            /* FALL THRU */
        case 1:
            a = *charptr;
            if (a == 0x7F || a == 0xDF || a == 0xEF || a == 0xF4) {
                return false;
            }
            charptr[0]++;
            break;
    }

    return true;
}

/*
 * EUC-JP character incrementer function.
 *
 * If the sequence starts with SS2 (0x8e), it must be a two-byte sequence
 * representing JIS X 0201 characters with the second byte ranging between
 * 0xa1 and 0xdf.  We just increment the last byte if it's less than 0xdf,
 * and otherwise rewrite the whole sequence to 0xa1 0xa1.
 *
 * If the sequence starts with SS3 (0x8f), it must be a three-byte sequence
 * in which the last two bytes range between 0xa1 and 0xfe.  The last byte
 * is incremented if possible, otherwise the second-to-last byte.
 *
 * If the sequence starts with a value other than the above and its MSB
 * is set, it must be a two-byte sequence representing JIS X 0208 characters
 * with both bytes ranging between 0xa1 and 0xfe.  The last byte is
 * incremented if possible, otherwise the second-to-last byte.
 *
 * Otherwise, the sequence is a single-byte ASCII character. It is
 * incremented up to 0x7f.
 */
static bool pg_eucjp_increment(unsigned char* charptr, int length)
{
    unsigned char c1, c2;
    int i;

    c1 = *charptr;

    switch (c1) {
        case SS2: /* JIS X 0201 */
            if (length != 2) {
                return false;
            }
            c2 = charptr[1];

            if (c2 >= 0xdf) {
                charptr[0] = charptr[1] = 0xa1;
            } else if (c2 < 0xa1) {
                charptr[1] = 0xa1;
            } else {
                charptr[1]++;
            }
            break;

        case SS3: /* JIS X 0212 */
            if (length != 3) {
                return false;
            }
            for (i = 2; i > 0; i--) {
                c2 = charptr[i];
                if (c2 < 0xa1) {
                    charptr[i] = 0xa1;
                    return true;
                } else if (c2 < 0xfe) {
                    charptr[i]++;
                    return true;
                }
            }

            /* Out of 3-byte code region */
            return false;

        default:
            // JIS X 0208?
            if (IS_HIGHBIT_SET(c1)) {
                if (length != 2) {
                    return false;
                }
                for (i = 1; i >= 0; i--) {
                    c2 = charptr[i];
                    if (c2 < 0xa1) {
                        charptr[i] = 0xa1;
                        return true;
                    } else if (c2 < 0xfe) {
                        charptr[i]++;
                        return true;
                    }
                }

                /* Out of 2 byte code region */
                return false;
            } else { /* ASCII, single byte */
                if (c1 > 0x7e) {
                    return false;
                }
                (*charptr)++;
            }
            break;
    }

    return true;
}
#endif /* !FRONTEND */

/*
 * -------------------------------------------------------------------
 * encoding info table
 * XXX must be sorted by the same order as enum pg_enc (in mb/pg_wchar.h)
 * -------------------------------------------------------------------
 */
pg_wchar_tbl pg_wchar_table[] = {
    {pg_ascii2wchar_with_len, pg_wchar2single_with_len, pg_ascii_mblen, pg_ascii_dsplen, pg_ascii_verifier, 1}, /* PG_SQL_ASCII
                                                                                                                 */
    {pg_eucjp2wchar_with_len, pg_wchar2euc_with_len, pg_eucjp_mblen, pg_eucjp_dsplen, pg_eucjp_verifier, 3}, /* PG_EUC_JP
                                                                                                              */
    {pg_euccn2wchar_with_len, pg_wchar2euc_with_len, pg_euccn_mblen, pg_euccn_dsplen, pg_euccn_verifier, 2}, /* PG_EUC_CN
                                                                                                              */
    {pg_euckr2wchar_with_len, pg_wchar2euc_with_len, pg_euckr_mblen, pg_euckr_dsplen, pg_euckr_verifier, 3}, /* PG_EUC_KR
                                                                                                              */
    {pg_euctw2wchar_with_len, pg_wchar2euc_with_len, pg_euctw_mblen, pg_euctw_dsplen, pg_euctw_verifier, 4}, /* PG_EUC_TW
                                                                                                              */
    {pg_eucjp2wchar_with_len, pg_wchar2euc_with_len, pg_eucjp_mblen, pg_eucjp_dsplen, pg_eucjp_verifier, 3}, /* PG_EUC_JIS_2004
                                                                                                              */
    {pg_gbk2wchar_with_len, pg_wchar2gbk_with_len, pg_gbk_mblen, pg_gbk_dsplen, pg_gbk_verifier, 2},  /* PG_GBK */
    {pg_utf2wchar_with_len, pg_wchar2utf_with_len, pg_utf_mblen, pg_utf_dsplen, pg_utf8_verifier, 4}, /* PG_UTF8 */
    {pg_mule2wchar_with_len, pg_wchar2mule_with_len, pg_mule_mblen, pg_mule_dsplen, pg_mule_verifier, 4}, /* PG_MULE_INTERNAL
                                                                                                           */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_LATIN1 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_LATIN2 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_LATIN3 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_LATIN4 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_LATIN5 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_LATIN6 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_LATIN7 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_LATIN8 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_LATIN9 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_LATIN10 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_WIN1256 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_WIN1258 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_WIN866 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_WIN874 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_KOI8R */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_WIN1251 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_WIN1252 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* ISO-8859-5 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* ISO-8859-6 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* ISO-8859-7 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* ISO-8859-8 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_WIN1250 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_WIN1253 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_WIN1254 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_WIN1255 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1}, /* PG_WIN1257 */
    {pg_latin12wchar_with_len,
        pg_wchar2single_with_len,
        pg_latin1_mblen,
        pg_latin1_dsplen,
        pg_latin1_verifier,
        1},                                                              /* PG_KOI8U */
    {pg_gb180302wchar_with_len,
        pg_wchar2gb18030_with_len,
        pg_gb18030_mblen,
        pg_gb18030_dsplen,
        pg_gb18030_verifier,
        4},                                                              /* PG_GB18030 */
    {pg_gb180302wchar_with_len,
        pg_wchar2gb18030_with_len,
        pg_gb18030_mblen,
        pg_gb18030_dsplen,
        pg_gb18030_verifier,
        4},                                                             /* PG_GB18030_2022 */
    {0, 0, pg_sjis_mblen, pg_sjis_dsplen, pg_sjis_verifier, 2},          /* PG_SJIS */
    {0, 0, pg_big5_mblen, pg_big5_dsplen, pg_big5_verifier, 2},          /* PG_BIG5 */
    {0, 0, pg_uhc_mblen, pg_uhc_dsplen, pg_uhc_verifier, 2},             /* PG_UHC */
    {0, 0, pg_johab_mblen, pg_johab_dsplen, pg_johab_verifier, 3},       /* PG_JOHAB */
    {0, 0, pg_sjis_mblen, pg_sjis_dsplen, pg_sjis_verifier, 2}           /* PG_SHIFT_JIS_2004 */
};

/* returns the byte length of a word for mule internal code */
int pg_mic_mblen(const unsigned char* mbstr)
{
    return pg_mule_mblen(mbstr);
}

/*
 * Returns the byte length of a multibyte character.
 */
int pg_encoding_mblen(int encoding, const char* mbstr)
{
    Assert(PG_VALID_ENCODING(encoding));

    return ((encoding >= 0 && (size_t)encoding < sizeof(pg_wchar_table) / sizeof(pg_wchar_tbl))
                ? ((*pg_wchar_table[encoding].mblen)((const unsigned char*)mbstr))
                : ((*pg_wchar_table[PG_SQL_ASCII].mblen)((const unsigned char*)mbstr)));
}

/*
 * Returns the display length of a multibyte character.
 */
int pg_encoding_dsplen(int encoding, const char* mbstr)
{
    Assert(PG_VALID_ENCODING(encoding));

    return ((encoding >= 0 && (size_t)encoding < sizeof(pg_wchar_table) / sizeof(pg_wchar_tbl))
                ? ((*pg_wchar_table[encoding].dsplen)((const unsigned char*)mbstr))
                : ((*pg_wchar_table[PG_SQL_ASCII].dsplen)((const unsigned char*)mbstr)));
}

/*
 * Verify the first multibyte character of the given string.
 * Return its byte length if good, -1 if bad.  (See comments above for
 * full details of the mbverify API.)
 */
int pg_encoding_verifymb(int encoding, const char* mbstr, int len)
{
    Assert(PG_VALID_ENCODING(encoding));

    return ((encoding >= 0 && (size_t)encoding < sizeof(pg_wchar_table) / sizeof(pg_wchar_tbl))
                ? ((*pg_wchar_table[encoding].mbverify)((const unsigned char*)mbstr, len))
                : ((*pg_wchar_table[PG_SQL_ASCII].mbverify)((const unsigned char*)mbstr, len)));
}

int pg_encoding_verifymbchar(int encoding, const char* mbstr, int len)
{
    int ok_bytes = pg_encoding_verifymb(encoding, mbstr, len);
    if (ok_bytes == 0) {
        return -1;
    }

    return ok_bytes;
}

int pg_encoding_verifymbstr(int encoding, const char* mbstr, int len)
{
    mbverifier mbverify;
    int ok_bytes;

    Assert(PG_VALID_ENCODING(encoding));

    if (pg_encoding_max_length(encoding) <= 1) {
        const char* nullpos = (const char*)memchr(mbstr, 0, len);

        if (nullpos == NULL) {
            return len;
        }

        return nullpos - mbstr;
    }

    mbverify = pg_wchar_table[encoding].mbverify;
    ok_bytes = 0;

    while (len > 0) {
        int l;

        if (!IS_HIGHBIT_SET(*mbstr)) {
            if (*mbstr != '\0') {
                ok_bytes++;
                mbstr++;
                len--;
                continue;
            }

            return ok_bytes;
        }

        l = (*mbverify)((const unsigned char*)mbstr, len);

        if (l < 0) {
            return ok_bytes;
        }

        mbstr += l;
        len -= l;
        ok_bytes += l;
    }

    return ok_bytes;
}

/*
 * fetch maximum length of a given encoding
 */
int pg_encoding_max_length(int encoding)
{
    return PG_VALID_ENCODING(encoding) ? pg_wchar_table[encoding].maxmblen : pg_wchar_table[PG_SQL_ASCII].maxmblen;
}

#ifdef WIN32
#ifndef FRONTEND

/*
 * fetch maximum length of the encoding for the current database
 */
int pg_database_encoding_max_length(void)
{
    return pg_wchar_table[GetDatabaseEncoding()].maxmblen;
}

/*
 * Verify mbstr to make sure that it is validly encoded in the current
 * database encoding.  Otherwise same as pg_verify_mbstr().
 */
bool pg_verifymbstr(const char* mbstr, int len, bool noError)
{
    return pg_verify_mbstr_len(GetDatabaseEncoding(), mbstr, len, noError) >= 0;
}
#endif
#else
int pg_database_encoding_max_length(void)
{
    return pg_wchar_table[GetDatabaseEncoding()].maxmblen;
}

/*
 * Verify mbstr to make sure that it is validly encoded in the current
 * database encoding.  Otherwise same as pg_verify_mbstr().
 */
bool pg_verifymbstr(const char* mbstr, int len, bool noError)
{
    return pg_verify_mbstr_len(GetDatabaseEncoding(), mbstr, len, noError) >= 0;
}
#endif

#ifndef FRONTEND
/*
 * get the character incrementer for the encoding for the current database
 */
mbcharacter_incrementer pg_database_encoding_character_incrementer(void)
{
    /*
     * Eventually it might be best to add a field to pg_wchar_table[], but for
     * now we just use a switch.
     */
    switch (GetDatabaseEncoding()) {
        case PG_UTF8:
            return pg_utf8_increment;

        case PG_EUC_JP:
            return pg_eucjp_increment;

        default:
            return pg_generic_charinc;
    }
}

/*
 * Verify mbstr to make sure that it is validly encoded in the specified
 * encoding.
 */
bool pg_verify_mbstr(int encoding, const char* mbstr, int len, bool noError)
{
    return pg_verify_mbstr_len(encoding, mbstr, len, noError) >= 0;
}

#endif // FRONTEND

/*
 * Verify mbstr to make sure that it is validly encoded in the specified
 * encoding.
 *
 * mbstr is not necessarily zero terminated; length of mbstr is
 * specified by len.
 *
 * If OK, return length of string in the encoding.
 * If a problem is found, return -1 when noError is
 * true; when noError is false, ereport() a descriptive message.
 */
int pg_verify_mbstr_len(int encoding, const char* mbstr, int len, bool noError)
{
    mbverifier mbverify;
    int mb_len;
#ifndef FRONTEND
    bool bulkload_illegal_chars_conversion = false;
#endif

    Assert(PG_VALID_ENCODING(encoding));

#ifndef FRONTEND
    if (u_sess->cmd_cxt.bulkload_compatible_illegal_chars) {
        bulkload_illegal_chars_conversion = true;
    } else if (u_sess->mb_cxt.insertValuesBind_compatible_illegal_chars) {
        bulkload_illegal_chars_conversion = true;
    }
#endif

    /*
     * In single-byte encodings, we need only reject nulls (\0).
     */
    if (pg_encoding_max_length(encoding) <= 1) {
        const char* nullpos = (char*)memchr(mbstr, 0, len);

        if (nullpos == NULL) {
            return len;
        }
        if (noError) {
            return -1;
        }
#ifndef FRONTEND
        if (bulkload_illegal_chars_conversion) {
            char* curpos = (char*)nullpos;
            int left_len = len - (nullpos - mbstr);

            /*
             * check whether '\0' exists char by char.
             */
            while (left_len > 0) {
                if ('\0' == *curpos) {
                    *curpos = ' ';
                }

                curpos++;
                left_len--;
            }

            return len;
        } else {
            report_invalid_encoding(encoding, nullpos, 1);
        }
#else
        report_invalid_encoding(encoding, nullpos, 1);
#endif
    }

    /* fetch function pointer just once */
    mbverify = pg_wchar_table[encoding].mbverify;

    mb_len = 0;

    while (len > 0) {
        int l;

        /* fast path for ASCII-subset characters */
        if (!IS_HIGHBIT_SET(*mbstr)) {
            if (*mbstr != '\0') {
                mb_len++;
                mbstr++;
                len--;
                continue;
            }
            if (noError) {
                return -1;
            }
#ifndef FRONTEND
            if (bulkload_illegal_chars_conversion) {
                *(char*)mbstr = ' ';
                mb_len++;
                mbstr++;
                len--;
                continue;
            } else {
                report_invalid_encoding(encoding, mbstr, len);
            }
#else
            report_invalid_encoding(encoding, mbstr, len);
#endif
        }

        l = (*mbverify)((const unsigned char*)mbstr, len);

        if (l < 0) {
            if (noError) {
                return -1;
            }
#ifndef FRONTEND
            if (bulkload_illegal_chars_conversion) {
                /*
                 * use '?' as illegal chars conversion
                 */
                *(char*)mbstr = '?';

                mbstr++;
                len--;
                mb_len++;
                continue;
            } else {
                report_invalid_encoding(encoding, mbstr, len);
            }
#else
            report_invalid_encoding(encoding, mbstr, len);
#endif
        }

        mbstr += l;
        len -= l;
        mb_len++;
    }
    return mb_len;
}

#ifdef FRONTEND
void report_invalid_encoding(int, const char*, int)
{

}
#endif // FRONTEND

#ifndef FRONTEND

/*
 * check_encoding_conversion_args: check arguments of a conversion function
 *
 * "expected" arguments can be either an encoding ID or -1 to indicate that
 * the caller will check whether it accepts the ID.
 *
 * Note: the errors here are not really user-facing, so elog instead of
 * ereport seems sufficient.  Also, we trust that the "expected" encoding
 * arguments are valid encoding IDs, but we don't trust the actuals.
 */
void check_encoding_conversion_args(
    int src_encoding, int dest_encoding, int len, int expected_src_encoding, int expected_dest_encoding)
{
    if (!PG_VALID_ENCODING(src_encoding)) {
        ereport(ERROR, (errcode(ERRCODE_SYSTEM_ERROR), errmsg("invalid source encoding ID: %d", src_encoding)));
    }

    if (src_encoding != expected_src_encoding && expected_src_encoding >= 0) {
        ereport(ERROR,
            (errcode(ERRCODE_SYSTEM_ERROR),
                errmsg("expected source encoding \"%s\", but got \"%s\"",
                    pg_enc2name_tbl[expected_src_encoding].name,
                    pg_enc2name_tbl[src_encoding].name)));
    }

    if (!PG_VALID_ENCODING(dest_encoding)) {
        ereport(ERROR, (errcode(ERRCODE_SYSTEM_ERROR), errmsg("invalid destination encoding ID: %d", dest_encoding)));
    }

    if (dest_encoding != expected_dest_encoding && expected_dest_encoding >= 0) {
        ereport(ERROR,
            (errcode(ERRCODE_SYSTEM_ERROR),
                errmsg("expected destination encoding \"%s\", but got \"%s\"",
                    pg_enc2name_tbl[expected_dest_encoding].name,
                    pg_enc2name_tbl[dest_encoding].name)));
    }

    if (len < 0) {
        ereport(ERROR, (errcode(ERRCODE_SYSTEM_ERROR), errmsg("encoding conversion length must not be negative")));
    }
}

/*
 * report_invalid_encoding: complain about invalid multibyte character
 *
 * note: len is remaining length of string, not length of character;
 * len must be greater than zero, as we always examine the first byte.
 */
void report_invalid_encoding(int encoding, const char* mbstr, int len)
{
    int l = pg_encoding_mblen(encoding, mbstr);
    char buf[8 * 5 + 1];
    char* p = buf;
    int j, jlimit;
    int rc = -1;
    int bufLen = sizeof(buf);
    
    jlimit = Min(l, len);
    jlimit = Min(jlimit, 8); /* prevent buffer overrun */

    for (j = 0; j < jlimit; j++) {
        rc = sprintf_s(p, bufLen, "0x%02x", (unsigned char)mbstr[j]);
        securec_check_ss(rc, "\0", "\0");
        p += rc;
        bufLen -= rc;
        if (j < jlimit - 1) {
            rc = sprintf_s(p, bufLen, " ");
            securec_check_ss(rc, "\0", "\0");
            p += rc;
            bufLen -= rc;
        }
    }

    ereport(ERROR,
        (errcode(ERRCODE_CHARACTER_NOT_IN_REPERTOIRE),
            errmsg("invalid byte sequence for encoding \"%s\": %s", pg_enc2name_tbl[encoding].name, buf)));
}

/*
 * report_untranslatable_char: complain about untranslatable character
 *
 * note: len is remaining length of string, not length of character;
 * len must be greater than zero, as we always examine the first byte.
 */
void report_untranslatable_char(int src_encoding, int dest_encoding, const char* mbstr, int len)
{
    int l = pg_encoding_mblen(src_encoding, mbstr);
    char buf[8 * 5 + 1];
    char* p = buf;
    int j, jlimit;

    jlimit = Min(l, len);
    jlimit = Min(jlimit, 8); /* prevent buffer overrun */

    for (j = 0; j < jlimit; j++) {
        p += sprintf_s(p, sizeof(buf), "0x%02x", (unsigned char)mbstr[j]);
        if (j < jlimit - 1) {
            p += sprintf_s(p, sizeof(buf), " ");
        }
    }

    /* omit untranslatable character error, report it in log
     * just works for local ->utf8 encoding translation.
     */
    if (u_sess->attr.attr_common.omit_encoding_error && (PG_UTF8 == dest_encoding)) {
        ereport(LOG,
            (errcode(ERRCODE_UNTRANSLATABLE_CHARACTER),
                errmsg("character with byte sequence %s in encoding \"%s\" has no equivalent in encoding \"%s\"",
                    buf,
                    pg_enc2name_tbl[src_encoding].name,
                    pg_enc2name_tbl[dest_encoding].name)));
    } else {
        ereport(ERROR,
            (errcode(ERRCODE_UNTRANSLATABLE_CHARACTER),
                errmsg("character with byte sequence %s in encoding \"%s\" has no equivalent in encoding \"%s\"",
                    buf,
                    pg_enc2name_tbl[src_encoding].name,
                    pg_enc2name_tbl[dest_encoding].name)));
    }
}

/*
 * add_invalid_encoding: add invalid encoding info to current CopyState illegal_chars_error list;
 *
 * note: len is remaining length of string, not length of character;
 * len must be greater than zero, as we always examine the first byte.
 *
 */
void add_invalid_encoding(int encoding, const char* mbstr, int len, List** err_info_list, int err_offset)
{
    return;
    int l = pg_encoding_mblen(encoding, mbstr);
    char buf[40];
    char* p = buf;
    int j, jlimit;
    int rc = -1;
    int buf_left_size = sizeof(buf);

    if (u_sess->mb_cxt.insertValuesBind_compatible_illegal_chars) {
        return;
    }

    Assert(err_info_list);

    jlimit = Min(l, len);
    jlimit = Min(jlimit, 8); /* prevent buffer overrun */

    for (j = 0; j < jlimit; j++) {
        rc = sprintf_s(p, buf_left_size, "0x%02x", (unsigned char)mbstr[j]);
        securec_check_ss(rc, "\0", "\0");

        p += rc;
        buf_left_size -= rc;

        if (j < jlimit - 1) {
            rc = sprintf_s(p, buf_left_size, " ");
            securec_check_ss(rc, "\0", "\0");

            p += rc;
            buf_left_size -= rc;
        }
    }

    IllegalCharErrInfo* errInfo = (IllegalCharErrInfo*)palloc0(sizeof(IllegalCharErrInfo));
    errInfo->err_info = (char*)palloc0(sizeof(buf));
    /*
     * record the original invalid encoding info.
     */
    rc = memcpy_s(errInfo->err_info, sizeof(buf), buf, sizeof(buf));
    securec_check(rc, "", "");
    /*
     * record the original or converted invalid encoding offset and encoding.
     */
    errInfo->err_offset = err_offset;
    errInfo->dest_encoding = encoding;
    /*
     * repocrd the original error code.
     */
    errInfo->err_code = ERRCODE_CHARACTER_NOT_IN_REPERTOIRE;
    *err_info_list = lappend(*err_info_list, errInfo);

    return;
}

/*
 * add_untranslatable_char: add untranslatable character to current CopyState illegal_chars_error list;
 *
 * note: len is remaining length of string, not length of character;
 * len must be greater than zero, as we always examine the first byte.
 */
void add_untranslatable_char(
    int src_encoding, int dest_encoding, const char* mbstr, int len, List** err_info_list, int err_offset)
{
    return;
    int l = pg_encoding_mblen(src_encoding, mbstr);
    char buf[40];
    char* p = buf;
    int j, jlimit;
    int rc = -1;
    int buf_left_size = sizeof(buf);

    if (u_sess->mb_cxt.insertValuesBind_compatible_illegal_chars) {
        return;
    }
    Assert(err_info_list);

    jlimit = Min(l, len);
    jlimit = Min(jlimit, 8); /* prevent buffer overrun */

    for (j = 0; j < jlimit; j++) {
        rc = sprintf_s(p, buf_left_size, "0x%02x", (unsigned char)mbstr[j]);
        securec_check_ss(rc, "\0", "\0");

        p += rc;
        buf_left_size -= rc;

        if (j < jlimit - 1) {
            rc = sprintf_s(p, buf_left_size, " ");
            securec_check_ss(rc, "\0", "\0");

            p += rc;
            buf_left_size -= rc;
        }
    }

    /* omit untranslatable character error, report it in log
     * just works for local ->utf8 encoding translation.
     */
    if (u_sess->attr.attr_common.omit_encoding_error && (PG_UTF8 == dest_encoding)) {
        ereport(LOG,
            (errcode(ERRCODE_UNTRANSLATABLE_CHARACTER),
                errmsg("character with byte sequence %s in encoding \"%s\" has no equivalent in encoding \"%s\"",
                    buf,
                    pg_enc2name_tbl[src_encoding].name,
                    pg_enc2name_tbl[dest_encoding].name)));
    }

    IllegalCharErrInfo* errInfo = (IllegalCharErrInfo*)palloc0(sizeof(IllegalCharErrInfo));
    errInfo->err_info = (char*)palloc0(sizeof(buf));

    /*
     * record the original invalid encoding info.
     */
    rc = memcpy_s(errInfo->err_info, sizeof(buf), buf, sizeof(buf));
    securec_check(rc, "", "");
    /*
     * record the original or converted invalid encoding position and encodings.
     */
    errInfo->err_offset = err_offset;
    errInfo->src_encoding = src_encoding;
    errInfo->dest_encoding = dest_encoding;
    /*
     * repocrd the original error code.
     */
    errInfo->err_code = ERRCODE_UNTRANSLATABLE_CHARACTER;
    *err_info_list = lappend(*err_info_list, errInfo);

    return;
}

#endif /* !FRONTEND */
